Method and apparatus for dispensing material on a substrate

ABSTRACT

A dispensing apparatus includes a frame, a support coupled to the frame, a gantry coupled to the frame, a first dispensing unit coupled to the gantry, a second dispensing unit coupled to the gantry, and an imaging system coupled to one of the frame and the gantry. The imaging system may be configured to capture at least one image of a first pattern and a second pattern, with the second pattern being identical to the first pattern. The dispensing apparatus further includes a controller configured to verify whether the first pattern and the second pattern are properly positioned on the support with respect to one another based on the at least one captured image to permit simultaneous dispense operations of the first dispensing unit on the first pattern and the second dispensing unit on the second pattern. Other embodiments and methods of dispensing are further disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.12/054,621 filed on Mar. 25, 2008, entitled METHOD AND APPARATUS FORDISPENSING MATERIAL ON A SUBSTRATE, which is a continuation-in-part ofU.S. patent application Ser. No. 11/809,590, filed Jun. 1, 2007 (nowU.S. Pat. No. 7,833,572), entitled METHOD AND APPARATUS FOR DISPENSING AVISCOUS MATERIAL ON A SUBSTRATE, all of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates generally to methods and apparatus fordispensing a viscous material on a substrate, such as a printed circuitboard, and more particularly to a method and an apparatus for dispensingmaterial on a substrate with enhanced efficiency.

2. Discussion of Related Art

There are several types of prior art dispensing systems used fordispensing precise amounts of liquid or paste for a variety ofapplications. One such application is the assembly of integrated circuitchips and other electronic components onto circuit board substrates. Inthis application, automated dispensing systems are used for dispensingdots of liquid epoxy or solder paste, or some other related material,onto circuit boards. Automated dispensing systems are also used fordispensing lines of underfill materials and encapsulents, which may beused to mechanically secure components to the circuit board. Exemplarydispensing systems described above include those manufactured anddistributed by Speedline Technologies, Inc. of Franklin, Mass.

In a typical dispensing system, a pump and dispenser assembly is mountedto a moving assembly or gantry for moving the pump and dispenserassembly along three mutually orthogonal axes (X, Y, Z) usingservomotors controlled by a computer system or controller. To dispense adot of liquid on a circuit board or other substrate at a desiredlocation, the pump and dispenser assembly is moved along the co-planarhorizontal X and Y axes until it is located over the desired location.The pump and dispenser assembly is then lowered along theperpendicularly oriented vertical Z axis until a nozzle/needle of thepump and dispenser assembly is at an appropriate dispensing height overthe substrate. The pump and dispenser assembly dispenses a dot ofliquid, is then raised along the Z axis, moved along the X and Y axes toa new location, and is lowered along the Z axis to dispense the nextliquid dot. For applications such as encapsulation or underfilling asdescribed above, the pump and dispenser assembly is typically controlledto dispense lines of material as the pump and dispenser are moved in theX and Y axes along the desired path of the lines.

The production rate of such dispensing systems, in some cases, may belimited by the rate at which a particular dispense pump assembly canaccurately and controllably dispense dots or lines of material. In othercases, the production rate of such systems may be limited by the rate atwhich parts can be loaded into and out of the machine. In still othercases, the production rate of such systems may be limited by processrequirements, such as the time required to heat a substrate to aparticular temperature, or the time required for a dispensed material toflow, as in underfill applications. In all cases and applications, thereis some limit to the throughput capability of a single dispense system.

During the manufacture of integrated circuits, production requirementsoften exceed the throughput capabilities of a single dispensing system.To overcome the throughput limitations of a single dispensing system,various strategies are applied to improve the production process.

BRIEF SUMMARY OF THE INVENTION

One aspect of the invention is directed to a dispensing apparatus fordispensing viscous material on an electronic substrate. In a certainembodiment, the dispensing apparatus comprises: a frame; a supportcoupled to the frame to receive electronic substrates; a firstdispensing unit configured to dispense viscous material; a seconddispensing unit configured to dispense viscous material; a gantrycoupled to the frame, the gantry comprising a first Z drive mechanismconfigured to support the first dispensing unit, the first Z drivemechanism being configured to lower the first dispensing unit toward afirst electronic substrate pattern when performing a dispense operation,and a second Z drive mechanism configured to support the seconddispensing unit, the second Z drive mechanism being configured to lowerthe second dispensing unit toward a second electronic substrate patternwhen performing a dispense operation, wherein the second Z drivemechanism is capable of being adjusted relative to the first Z drivemechanism a predetermined distance; and a controller configured tocontrol a dispense operation of the first dispensing unit on the firstelectronic substrate pattern and a dispense operation of the seconddispensing unit on the second electronic substrate pattern.

Embodiments of the dispensing apparatus may include a vision systemcoupled to the gantry to align the first dispensing unit with the firstelectronic substrate and the second dispensing unit with the secondelectronic substrate. In one embodiment, the first and second dispensingunit each comprises a non-contact-type dispensing unit. In a certainembodiment, the non-contact-type dispensing unit is configured to streamviscous material onto the electronic substrate. In another embodiment,the non-contact-type dispensing unit is configured to launch viscousmaterial at a location on the electronic substrate.

Another aspect of the invention is directed to a method of dispensingviscous material on an electronic substrate comprising: delivering afirst electronic substrate pattern to a dispense position; delivering asecond electronic substrate pattern to a dispense position; aligning thefirst electronic substrate pattern with a first dispensing unit;positioning the second dispensing unit a predetermined distance from thefirst dispensing unit; dispensing material from the first dispensingunit at desired locations on the first electronic substrate pattern; anddispensing material from the second dispensing unit at desired locationson the second electronic substrate pattern.

Embodiments of the invention may include dispensing material from thefirst dispensing unit by lowering the first dispensing unit toward thefirst electronic substrate pattern and/or dispensing material from thesecond dispensing unit by lowering the second dispensing unit toward thesecond electronic substrate pattern.

Yet another aspect of the invention is directed to a method ofdispensing viscous material on an electronic substrate comprising:delivering first and second electronic substrate patterns to respectivedispense positions; positioning a first dispensing unit over the firstelectronic substrate pattern; positioning a second dispensing unit apredetermined distance from the first dispensing unit; dispensingmaterial from the first dispensing unit at desired locations on thefirst electronic substrate pattern, wherein dispensing material from thefirst dispensing unit comprises lowering the first dispensing unittoward the first electronic substrate pattern; and dispensing materialfrom the second dispensing unit at desired locations on the secondelectronic substrate pattern, wherein dispensing material from thesecond dispensing unit comprises, lowering the second dispensing unittoward the second electronic substrate pattern.

Embodiments of the invention may include determining the predetermineddistance by identifying a first point of reference associated with thefirst electronic substrate pattern and a second point of referenceassociated with the second electronic substrate pattern.

A further aspect of the invention is directed to a method of dispensingviscous material on an electronic substrate comprising the followingsteps: (1) identifying positions of fiducial locations on first andsecond electronic substrates; (2) positioning a second dispensing unit apredetermined distance from a first dispensing unit based on thefiducial locations; (3) moving the first dispensing unit to a firstdispense location on a first electronic substrate; (4) dispensing at thefirst dispense location on the first electronic substrate; (5) movingthe second dispensing unit to a first dispense location on the secondelectronic substrate; (6) dispensing at the first dispense location onthe second electronic substrate; and (7) repeating steps (3) through (6)for each remaining dispense location on the first and second electronicsubstrates.

Embodiments of the invention may further include calibrating a distancebetween first and second dispensing units and a camera. In oneembodiment, steps (4) and (6) occur without contacting the electronicsubstrate. In a certain embodiment, steps (4) and (6) are achieved byusing a non-contact-type dispensing unit configured to stream viscousmaterial onto the electronic substrate. In another embodiment, steps (4)and (6) are achieved by using a non-contact-type dispensing unitconfigured to launch viscous material at a location on the electronicsubstrate. Steps (3) and (5) may be achieved by a gantry capable ofmoving a dispensing unit in X axis and Y axis directions, in which thegantry is incapable of moving the dispensing unit in a Z axis direction.

One aspect of the disclosure is directed to a dispensing apparatuscomprises a frame, a support coupled to the frame, the support beingconfigured to support at least one electronic substrate, a gantrycoupled to the frame, a first dispensing unit coupled to the gantry, thefirst dispensing unit being configured to dispense material, a seconddispensing unit coupled to the gantry, the second dispensing unit beingconfigured to dispense material, an imaging system coupled to one of theframe and the gantry, the imaging system being configured to capture atleast one image of a first pattern and a second pattern, the secondpattern being identical to the first pattern, and a controllerconfigured to verify whether the first pattern and the second patternare properly positioned on the support with respect to one another basedon the at least one captured image to permit simultaneous dispenseoperations of the first dispensing unit on the first pattern and thesecond dispensing unit on the second pattern.

Embodiments of the dispensing apparatus may include the gantrycomprising at least one Z drive mechanism configured to support andlower the first dispensing unit and the second dispensing unit whenperforming a dispense operation with at least one of the firstdispensing unit and the second dispensing unit. In one embodiment, theat least one Z drive mechanism comprises a first Z drive mechanismconfigured to support the first dispensing unit, the first Z drivemechanism being configured to lower the first dispensing unit toward thefirst pattern when performing a dispense operation, and a second Z drivemechanism configured to support the second dispensing unit, the second Zdrive mechanism being configured to lower the second dispensing unittoward the second pattern when performing a dispense operation. Thesecond dispensing unit is capable of being adjusted a predetermineddistance from the first dispensing unit based on the at least onecaptured image. In a certain embodiment, the first and second dispensingunits may each comprise a non-contact-type dispensing unit. In anotherembodiment, the non-contact-type dispensing unit is configured to streamor launch material onto the electronic substrate.

Another aspect of the disclosure is directed to a dispensing apparatuscomprising a gantry, at least two dispensing units coupled to thegantry, each of the at least two dispensing units including anon-contact-type dispensing unit configured to dispense material, animaging system coupled to the gantry, the imaging system beingconfigured to capture at least one image of a first pattern and a secondpattern, the second pattern being identical to the first pattern, and acontroller configured to verify whether the first pattern and the secondpattern are properly positioned on the support with respect to oneanother based on the at least one captured image to permit simultaneousdispense operations of the first dispensing unit on the first patternand the second dispensing unit on the second pattern.

Embodiments of the dispensing apparatus may include configuring thenon-contact-type dispensing unit to stream material onto the electronicsubstrate. In another embodiment, the non-contact-type dispensing unitis configured to launch material at a location on the electronicsubstrate.

A further aspect of the disclosure is directed to a method of dispensingmaterial comprising: delivering an electronic substrate to a dispenseposition, the electronic substrate having at least two identicalpatterns; capturing at least one image of the at least two patterns; anddetermining whether the at least two patterns are properly positioned toperform simultaneous dispense operations on the at least two patternsbased on the captured image.

Embodiments of the method may include, when the at least two patternsare not properly positioned, performing a first dispense operation on afirst pattern of the at least two patterns and performing a seconddispense operation on a second pattern of the at least two patterns. Inone embodiment, the second dispense operation is performed after thefirst dispense operation. If the at least two patterns are properlypositioned, dispense operations may be simultaneously performed on theat least two patterns. A first dispensing unit may be positioned over afirst location of a first pattern and a second dispensing unit may bepositioned over a first location of a second pattern. Dispenseoperations may be performed with the first and second dispensing units.In a certain embodiment, the second dispensing unit is spaced from thefirst dispensing unit a predetermined distance. In yet anotherembodiment, material may be dispensed from the first and seconddispensing units on respective first locations of the first and secondpatterns. The arrangement is such that the first dispensing unit may bemoved over a second location of the first pattern and the seconddispensing unit may be moved over a second location of the secondpattern of the electronic substrate. Material may be dispensed from thefirst and second dispensing units on respective second locations of thefirst and second patterns. When dispensing material from the firstdispensing unit, the first dispensing unit may be lowered toward thefirst pattern. Similarly, when dispensing material from the seconddispensing unit, the second dispensing unit may be lowered toward thesecond pattern.

In yet another aspect of the disclosure, a method of dispensing materialcomprises the following steps: (1) identifying positions of more thanone location on an electronic substrate; (2) determining whether adispense location of a first pattern and a dispense location of a secondpattern are properly positioned to perform simultaneous dispenseoperations on the first and second patterns based on the identifiedpositions; (3) if properly positioned, moving a first dispensing unit toa dispense location on the first pattern and moving a second dispensingunit to a dispense location on the second pattern, the dispense locationof the first pattern corresponding with the dispense location on thesecond pattern; (4) simultaneously dispensing at the dispense locationon the first pattern with the first dispensing unit and at the dispenselocation on the second pattern with the second dispensing unit; and (5)repeating steps (3) and (4) for each remaining dispense location on thefirst and second patterns of the electronic substrate.

Embodiments of the method may include: calibrating a distance betweenthe first and second dispensing units and a camera; performing step (4)without contacting the electronic substrate; performing step (4) byusing a non-contact-type dispensing unit configured to at least one ofstream and launch material onto the electronic substrate; and performingstep (3) by a gantry capable of moving a dispensing unit in X axis and Yaxis directions.

The present disclosure will be more fully understood after a review ofthe following figures, detailed description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is a side schematic view of a dispenser; and

FIGS. 2-4 are schematic views of a dispenser; and

FIGS. 5 and 6 are schematic views of another dispenser of an embodimentof the disclosure used to perform methods of the disclosure.

DETAILED DESCRIPTION OF THE INVENTION

For the purposes of illustration only, and not to limit the generality,the disclosure will now be described in detail with reference to theaccompanying figures. This disclosure is not limited in its applicationto the details of construction and the arrangement of components setforth in the following description or illustrated in the drawings. Theteachings disclosed herein are capable of other embodiments and of beingpracticed or being carried out in various ways. Also the phraseology andterminology used herein is for the purpose of description and should notbe regarded as limiting. The use of “including,” “comprising,” “having,”“containing,” “involving,” and variations thereof herein, is meant toencompass the items listed thereafter and equivalents thereof as well asadditional items.

As mentioned above, in some cases, multiple independent dispensingsystems are sometimes used to increase the production of dispenseoperations. This solution is often expensive, requiring multiplemachines, additional manufacturing space and in some cases multiplemachine operators. In typical operations, manufacturing floor space isboth limited and expensive. It is therefore desirable to reduce the“footprint” of each manufacturing system on the manufacturing floor andto reduce the number of separate machines that need to be operated andmaintained.

For some applications, multiple instances of the same circuit patternare fabricated on a common substrate. A common example is a circuitpattern for a cell phone, wherein four or more patterns may be disposedon a single substrate. In such cases, there is often a fixed and uniformoffset between the multiple instances of the circuit patterns, which maybe disposed on a common substrate and separated from one another aftercompletion along perforations. Furthermore, it is known in the industrythat a dispensing system with multiple dispensing units or pumps may beutilized to increase throughput. In such systems, the offset distancebetween the multiple dispensing pumps may be adjusted to besubstantially the same as the offset distance between the multiplecircuit distances, and if the accuracy of this offset adjustment iswithin the accuracy requirements of the resultant dispense pattern, thenthe multiple dispensing pumps can be positioned simultaneously by asingle X, Y, Z gantry and operated simultaneously.

When a dispensing system is presented with a substrate or component tobe dispensed upon, it is typical that an automatic vision system is usedto locate and calibrate the actual position of the part and/or criticalfeatures within the part. This locating and calibrating allows thesystem to compensate for variations in either the substrate or componentitself or in the fixing of the substrate or component relative to thecoordinate system of the dispensing unit positioning system.

When multiple dispensing units or heads are utilized in parallel toachieve a high collective throughput, e.g., dispensing on two substratesat the same time, it is typical that the multiple dispensing units areprogrammed to perform substantially the same task on substantiallyidentical components. However, because of slight variations in eitherthe components themselves or in the fixing of the components relative tothe positioning systems, corrections may need to be appliedindependently to each of the multiple dispense units. Since thesecorrections are unique to each of the multiple dispense units, it isnecessary that each of the dispensing units be independently positionedrelative to its substrate. Accordingly, dispensers configured withmultiple dispensing units are more adapted for coarse dispensingapplications in which accurate dispensing is not critical.

One prior art system achieves high throughput by utilizing multipleindependent dispensing units and is described in U.S. patent applicationSer. No. 09/033,022, filed Mar. 2, 1998, now U.S. Pat. No. 6,007,631,which is incorporated herein by reference. This dispensing systemutilizes multiple independent dispensing units or heads. Each of themultiple dispensing units is mounted on a separate positioning systemand operates over an independent work area.

One other prior art system achieves high throughput by utilizingmultiple units and multiple pallets of parts and is described inprovisional U.S. patent application Ser. No. 60/432,483, filed Dec. 11,2002, now abandoned, and also in U.S. patent application Ser. No.10/661,830, filed Sep. 12, 2003, now abandoned, both of which areincorporate herein by reference.

It is desirable to achieve at least some of the throughput advantages ofthe multiple dispense units or heads while still providing the size andcost advantages of a single dispense system. Embodiments of thedisclosure described below achieve the throughput advantages of priorart dispensers described above while further reducing the footprint andcost by positioning multiple dispensing units above the surface of thesubstrates with a common gantry. Specifically, embodiments of thedisclosure are directed to dispensing units, methods of dispensing anddispensing systems that contain methods and apparatus of the disclosure.Embodiments of the disclosure can be used with dispensing systemplatforms offered under the brand name CAMALOT® by SpeedlineTechnologies, Inc. of Franklin, Mass.

FIG. 1 schematically illustrates a dispenser, generally indicated at 10,used to dispense a viscous material (e.g., adhesive, encapsulent, epoxy,solder paste, underfill material, etc.) or a semi-viscous material(e.g., soldering flux, etc.), or a substantially non-viscous material(e.g., an ink) onto an electronic substrate 12, such as a printedcircuit board or semiconductor wafer. The substrate 12 may embody anytype of surface or material upon which dispensing is required. Thedispenser 10 includes first and second dispensing units or heads,generally indicated at 14 and 16, respectively, and a controller 18 tocontrol the operation of the dispenser. Although two dispensing unitsare shown, it should be understood that more than two dispensing unitsmay be provided.

The dispenser 10 also includes a frame 20 having a base 22 forsupporting the substrate 12 and a gantry 24 movably coupled to the frame20 for supporting and moving the dispensing units 14, 16. As is wellknown in the art of printed circuit board fabrication, a conveyor system(not shown) may be used in the dispenser 10 to control loading andunloading of circuit boards to and from the dispenser. The gantry 24 canbe moved using motors under the control of the controller 18 in the Xaxis and Y axis directions to position the dispensing units atpredetermined locations over the circuit board.

Referring now to FIGS. 2-4, and more particularly to FIG. 2, the gantry24 may be configured to include a left-hand side rail 26, a right-handside rail 28 and a beam 30 that extends between the two side rails. Thebeam 30 is configured to move in a Y axis direction along the side rails26, 28 to achieve Y axis movement of the dispensing units 14, 16. X axismovement of the dispensing units 14, 16 is achieved by a carriage device32 mounted on the beam 30. Specifically, the carriage device 32 housesthe dispensing units 14, 16 and is configured to move along the lengthof the beam 30 in the X axis direction to move the dispensing units overdesired locations of the substrate 12 positioned on the base 22. In acertain embodiment, movement of the gantry 24 (i.e., movement of thebeam 30 and the carriage device 32) in the X-Y plane may be achieved byemploying ball screw mechanisms driven by respective motors as is wellknown in the art.

In one embodiment, the platform dispenser 10 described herein may embodyan FX-D® dispensing system sold by Speedline Technologies, Inc. ofFranklin, Mass. In another embodiment, the platform dispenser may embodya SMARTSTREAM™ dispensing system, which is also sold by SpeedlineTechnologies Inc.

The dispensing units 14, 16, as mentioned above, are capable ofachieving Z axis movement by means of independent Z drive mechanisms,which are designated at 34, 36, respectively, in FIGS. 2-4. The amountof Z axis movement may be determined by measuring the distance betweenthe tip of a needle (not shown) of one of the dispensing units 14 and/or16 and the substrate 12. When moving, one or both of the dispensingunits 14, 16 may be positioned at a nominal clearance height above thesubstrate 12. The clearance height may be maintained at a relativelyconsistent elevation above the substrate 12 when moving from onedispense location to another dispense location. Upon reaching apredetermined dispense location, the Z drive mechanism 34, 36 lowers itsrespective dispensing unit 14, 16 to the substrate so that dispensing ofmaterial on the substrate 12 may be achieved.

In certain embodiments, a common gantry that moves both of thedispensing units together may control the dispensing units. Thus, asingle Z drive mechanism may be provided. This configuration isparticularly suited for dispensing units that stream or launch viscousmaterial onto the circuit board. In one embodiment, the dispensing unitmay be of the type disclosed in U.S. patent application Ser. No.11/707,620, entitled METHOD AND APPARATUS FOR DISPENSING VISCOUSMATERIAL ON A SUBSTRATE, filed Feb. 16, 2007, which claims priority toU.S. Provisional Patent Application Ser. No. 60/856,508, entitled METHODAND APPARATUS FOR DISPENSING A VISCOUS MATERIAL ON A SUBSTRATE, filedNov. 3, 2006, both of which are incorporated herein by reference andassigned to the assignee of the present disclosure, SpeedlineTechnologies, Inc. of Franklin, Mass. With the dispensing unit disclosedin the non-provisional and provisional applications, viscous materialstreams onto the substrate between predetermined starting and stoppingpoints. In another embodiment, the dispensing unit may be of the typedisclosed in U.S. Pat. No. 5,747,102, entitled METHOD AND APPARATUS FORDISPENSING SMALL AMOUNTS OF LIQUID MATERIAL, issued May 5, 1998, whichis incorporated herein by reference. With the dispensing unit disclosedin this patent, viscous material is launched at a predetermined locationon the substrate. The dispensing units that stream or launch viscousmaterial may be referred to as non-contact dispensing units in which Zaxis movement is not required, but may be provided.

In one embodiment, to measure the height of the needle of the dispensingunit at a desired elevation above the circuit board, there is provided asystem for measuring the height of the dispenser needle above thecircuit board in the Z axis direction. In some height (or distance)measuring systems, physical contact is made between the measuring systemand the surface. One such height measuring system is described in U.S.Pat. No. 6,093,251, entitled APPARATUS FOR MEASURING THE HEIGHT OF ASUBSTRATE IN A DISPENSING SYSTEM, which is assigned to the assignee ofthe present disclosure, and is incorporated herein by reference.Specifically, U.S. Pat. No. 6,093,251 discloses a measuring probe thatis extendable between a reference point and a location on the circuitboard to measure the height of the substrate.

In other height measuring systems, a laser light source and an opticalsensing system are combined to measure the position of an object withoutmaking physical contact. An example of a non-contact measuring system ismanufactured and distributed by Micro-Epsilon Messtechnik GmbH ofOrtenburg, Germany. In other embodiments, the height measuring systemcan be incorporated to facilitate the measurement of and compensationfor variations in the vertical position of the top surface of thecircuit board.

Still referring particularly to FIG. 2, the dispensing units 14, 16 aremoved over the substrate 12 in such a manner to perform a dispenseoperation with one or both of the dispensing units. However, prior todispensing, the position of the substrate 12 with respect to thedispensing units 14, 16 is determined so that accurate dispensing maytake place. Specifically, the carriage device 32 includes an opticalelement or camera 38 that is configured to take an image of thesubstrate 12. The camera 38 may be referred to herein as a “visionsystem” or an “imaging system.” To align the substrate 12 with thedispensing units 14, 16 and gantry 24, images of at least two fiducials(44, 46) are taken by the camera 38. If the substrate 12 is out ofposition, the gantry 24 may be manipulated to account for the actualposition of the substrate. In one embodiment, the camera 38 may becalibrated to determine camera-to-needle offset distances for each ofthe dispensing units 14, 16. Alternatively, the operator of thedispenser 50 may program the camera-to-needle offset distances basedupon preexisting information.

FIG. 3 illustrates a substrate 12 in an exaggerated skewed position. Asshown, the bottom edge 40 of the substrate 12 is at an angle 42 withrespect to the X axis. The gantry 24 moves the camera 38 over thesubstrate 12 to a first position in which the camera takes an image of afirst fiducial 44, which is positioned at the lower left-hand corner ofthe substrate 12 as viewed in FIG. 3. After capturing an image of thefirst fiducial 44, the gantry 24 moves the camera 38 over the substrate12 to a second position in which the camera takes an image of a secondfiducial 46, which is positioned at the upper right-hand corner of thesubstrate. Based on the images of the first and second fiducials 44, 46,the controller 18 can manipulate the gantry 24 to perform an accuratedispense operation with either one of the dispensing units. As shown inFIG. 3, dispense operations are performed at locations A₁, B₁ and C₁,for example. However, as can be appreciated, any number of dispenseoperations may be performed with one or both of the dispensing units 14,16. For example, instead of dispensing material at certain locations,lines of material may be dispensed on the substrate 12.

Turning to FIG. 4, the dispenser 10 may be configured to performdispense operations on two substrates 12A, 12B, which may be connectedwith one another (as with the cell phone configuration described above)or may be positioned separately on the base 22 in a tray, for example.For the substrates 12A, 12B illustrated in FIG. 4, the substrates areeach in an aligned or known position. Thus, dispensing operations atlocations A₁, B₁ and C₁ on the first substrate 12A with eitherdispensing unit 14 or 16 or both may be initiated. Once dispensing onthe first substrate 12A is finished, the carriage device may be movedalong the beam 30 in an X axis direction so that a dispensing operationmay take place at locations A₂, B₂ and C₂ on the second substrate 12Bwith either dispensing unit 14 or 16 or both. Obviously, the movement ofthe dispensing units 14, 16 is achieved, as discussed above, by movingthe beam 30 in the Y axis direction and the carriage device 32 in the Xaxis direction.

Referring to FIG. 5, there is generally designated at 50 a dispenser ofan embodiment of the disclosure. As shown, the dispenser 50 is similarto dispenser 10 shown in FIGS. 2-4. Accordingly, corresponding referencenumerals designate corresponding parts with respect to the dispenser 10shown in FIGS. 2-4 and the dispenser 50 shown in FIG. 5.

With dispenser 50, the second dispensing unit 16 is coupled to thecarriage device by an adjustable bracket 52. Thus, the second dispensingunit 16 may be offset from the first dispensing unit 14 a predetermineddistance D_(X). In a certain embodiment, the bracket 52 may bemanipulated to vary or change the distance D_(X) by any number ofmechanisms, such as a telescoping arm or a sliding bracket. Inparticular, as discussed above, the gantry 24 moves the camera 38 overthe substrate 12 to a first position in which the camera takes an imageof a first fiducial 44. After capturing an image of the first fiducial44, the gantry 24 moves the camera 38 over the substrate 12 to a secondposition in which the camera takes an image of a second fiducial 46.Based on the images of the first and second fiducials 44, 46, thecontroller 18 can manipulate the gantry 24 to perform an accuratedispense operation with either one of the dispensing units.

For the substrates 12A, 12B illustrated in FIG. 5, the substrates areillustrated in an aligned or known position to begin dispensingoperations at locations A₁, B₁ and C₁ on the first substrate 12A, thistime with the first dispensing unit 14, for example. Once dispensing onthe first substrate 12A is finished with the first dispensing unit 14,instead of moving the carriage device 32 in the X axis direction alongthe beam 30 as with the dispenser 10 shown in FIGS. 2-4, the carriagedevice 32 does not require any movement other than to move the seconddispensing unit 16 between the locations requiring material.

Specifically, the second dispensing unit 16 is in a suitable positionover the second substrate 12B to perform dispensing operations atlocations A₂, B₂ and C₂. As shown, the bracket 52 is coupled to thesecond dispensing unit 16 a predetermined distance D_(X), which may bemanipulated so that it achieves a length that is equivalent to thedistance L_(X) between the first and second substrates. In thisparticular example, the locations A₂, B₂ and C₂ on the second substrate12B correspond to the locations A₁, B₁ and C₁ on the first substrate12A. Again, the movement of the dispensing units 14, 16 is achieved inthe X-Y plane, as discussed above, by moving the carriage device 32 inthe X axis direction and by moving the beam 30 in the Y axis direction.Z axis movement is achieved by the independent Z drive mechanisms 34, 36associated with the first and second dispensing units 14, 16,respectively.

FIG. 6 illustrates the substrates 12A, 12B and dispenser 50 shown inFIG. 5, with the substrates in an exaggerated skewed position. As shown,the bottom edges 40A, 40B of substrates 12A, 12B, respectively, are atan angle 42 with respect to the X axis. To determine the locations orpositions of both substrates 12A, 12B, the gantry 24 moves the camera 38over the first substrate 12A to a first position in which the cameratakes an image of a first fiducial 44A of the first substrate 12A, whichis positioned at the lower left-hand corner of the first substrate asviewed in FIG. 6. After capturing an image of the first fiducial 44A,the gantry 24 moves the camera 38 over the first substrate 12A to asecond position in which the camera takes an image of a second fiducial46A, which is positioned at the upper right-hand corner of the firstsubstrate.

For the second substrate 12B, the gantry 24 moves the camera 38 over thesecond substrate to a third position in which the camera takes an imageof the third fiducial 44B, which is positioned at the lower left-handcorner of the second substrate. After capturing an image of the thirdfiducial 44B, the gantry 24 moves the camera 38 over the secondsubstrate 12B to a fourth position in which the camera takes an image ofthe fourth fiducial 46B, which is positioned at the upper right-handcorner of the second substrate. Based on the images of the first,second, third and fourth fiducials, 44A, 46A, 44B, 46B, respectively,the distance D_(X) of the second dispensing unit 16 may be manipulatedbased on the distance L_(X) between the first and second substrates 12A,12B. Specifically, the bracket 52 may be manipulated to establish thesecond dispensing unit 16 a predetermined distance from the firstdispensing unit 14.

As shown in FIG. 6, dispense operations are performed at locations A₁,B₁ and C₁ with the first dispensing unit 14 and dispense operations areperformed at locations A₂, B₂ and C₂ with the second dispensing unit 16.In one embodiment, dispensing may be achieved by first manipulating thefirst dispensing unit 14 to dispense material at locations A₁, B₁ and C₁and then manipulating the second dispensing unit 16 to dispense materialat locations A₂, B₂ and C₂. In another embodiment, the first dispensingunit 14 may be manipulated to dispense material at location A₁ and thenthe second dispensing unit 16 may be manipulated to dispense material atA₂. Next, the first dispensing unit 14 may be manipulated to dispensematerial at location B₁ and then the second dispensing unit 16 may bemanipulated to dispense material at B₂. And finally, the firstdispensing unit 14 may be manipulated to dispense material at locationC₁ and then the second dispensing unit 16 may be manipulated to dispensematerial at C₂. Some other dispense sequence may also be performed basedon the optimal movements of the first and second dispensing units 14,16.

Thus, for a dispenser having two dispensing units 14, 16 as shown inFIGS. 5 and 6, based on the determination of the locations of the first,second, third and fourth fiducials, 44A, 46A, 44B, 46B, respectively,the angle of the first and second substrates 12A, 12B with respect tothe X axis may be determined. As shown in FIG. 6, the L_(X1) and L_(Y1)offset distances may be determined so that accurate dispense operationsmay take place. Accordingly, for a dispenser having multiple dispensingunits, the distance and relative position of each of the multipledispensing units may be configured to match the distance and relativespacing between each of the multiple substrates or components. Aftercollecting and analyzing alignment information from an automatic visionalignment system, a first of the multiple dispensing units is positionedover a first dispense location on the first substrate or component.After performing a dispense operation, the gantry may be manipulated tomake any required X-Y plane position adjustment that may be necessary toalign a second of the multiple dispensing units over the correspondingfirst dispensing location of the second of the multiple substrates orcomponents. Since the distance and relative position between each of themultiple dispense units is substantially similar to, although notnecessarily identical to, the distance and relative position betweeneach of the multiple substrates or components, any such adjustment ofthe gantry will be very small and thus rapidly performed. Each of theremaining multiple dispense units may be similarly utilized to dispensematerial at the corresponding first dispense location on each of theremaining substrates or components before any large X and Y gantrymotion is required. However, if the number of substrates or componentsis greater than the number of dispense units, then the gantry may needto be repositioned to complete the dispensing operations on all of thesubstrates. The method is repeated to dispense each of the second andsubsequent dispense locations. It should be understood that steps may beinterchanged as may be dictated by either throughout or processimprovements.

As discussed above, in one embodiment, the dispensing units 14, 16 maybe mounted on separate Z drive mechanisms. This configuration enablesthe performance of independent operations when appropriate, includingbut not limited to dispensing, cleaning (as by an automatic needlecleaner, for example), purging and calibration (either the X/Y axesposition or the Z axis position). However, it should be noted that thedispenser 50 may be particularly suited for non-contact dispensing, suchas the streaming of material from the needle. When configured fornon-contact dispensing, the dispensing operation may be performed withthe two (or more) dispensing units that are mounted on a single Z drivemechanism.

With this particular configuration, the two dispensing units are bothpositioned over their respective locations on the two (or more)substrates. Specifically, when positioning the first dispensing unit 14nearly exactly over a given dispense position on the first substrate12A, the second dispensing unit 16 is in an approximately correctposition over the second substrate 12B. Next, the first dispensing unit14 performs a first dispense operation on the first substrate 12A. Oncecompleted, the second dispensing unit 16 is moved a minor amount tocorrect its location over the second substrate 12B so as to enable theperformance of a second dispense operation on the second substrate.Since non-contact dispensing does not require a Z axis direction ofmovement, having the first and second dispensing units 14, 16 mounted ona common Z drive mechanism does not preclude independent dispensing fromeach of the dispensing units.

As discussed above, when determining the offset distance betweenmultiple substrates, or multiple patterns within a single substrate, thecamera 38 may be operated to take images of known reference points, suchas fiducials, which are used to determine the offset distance. However,the offset distance may be determined by the operator of the dispenser10 during the set-up of the dispenser based on known configurations. Inaddition, as described above, the exact offset distance is notnecessary. A more coarse distance may be appropriate. Specifically,while a more precise offset distance would serve to minimize anycorrective move required of the second dispensing unit (or the firstdispensing unit if the second dispensing unit is first used), animprecise offset distance would not preclude or otherwise negativelyimpact a precise second dispense operation. The actual relative distancebetween the two or more dispensing units may be measured and thereforecorrected for inaccuracies in the setting of the offset distance.

In certain embodiments, when dispensing on multiple patterns provided ona single substrate, each pattern may have its own corresponding set oflocal alignment fiducials. Alternatively, the substrate may have one setof global fiducials used to align the entire substrate and thus themultiple patterns at once. In a typical process program, the locationsof many of the dispensing sites are known, generally being definedrelative to the alignment fiducial locations. Accordingly, once theactual locations of the fiducials have been measured using the camera38, the actual positions of the many dispense locations may becalculated, including those locations associated with multiple instancesof a repeated pattern. Since each of the multiple dispensing unitsmounted on the gantry has its own camera-to-needle offset distance,which may be separately learned or calibrated as described above, andsince each of the multiple dispensing units may be operated at separatetimes, the proper position corrections for each and every dispenselocation may be separately and accurately applied to each of themultiple dispensing units.

It should be observed that the dispenser 50 may be operated to performdispense operations with multiple dispensing units that operateindependently from each other. The camera to needle offset distance maybe calibrated by the dispenser, or be selected by the operator of thedispenser. Prior to dispensing, the camera-to-needle offset distancesmay be determined. Additionally, locations of the first and seconddispensing units may be calibrated to determine their respectivelocations prior to dispensing. Finally, the relative offset distancebetween each of the dispensing units may be nominally (not precisely)calculated to match the relative pitch between multiple instances of arepeated substrate pattern.

Thus, an exemplary dispense operation for two substrates or for twosubstrate patterns may consist of the following steps: delivering afirst electronic substrate pattern to a dispense position; delivering asecond electronic substrate pattern to a dispense position; aligning thefirst electronic substrate pattern with a first dispensing unit;positioning the second dispensing unit a predetermined distance from thefirst dispensing unit; dispensing material from the first dispensingunit at desired locations on the first electronic substrate pattern; anddispensing material from the second dispensing unit at desired locationson the second electronic substrate pattern. In certain embodiments, thestep of dispensing material from the first dispensing unit may compriselowering the first dispensing unit toward the first electronic substratepattern. Similarly, the step of dispensing material from the seconddispensing unit may comprise lowering the second dispensing unit towardthe second electronic substrate pattern.

Another exemplary dispense operation may consist of the following steps:delivering first and second electronic substrate patterns to respectivedispense positions; positioning a first dispensing unit over the firstelectronic substrate pattern; positioning a second dispensing unit apredetermined distance from the first dispensing unit; dispensingmaterial from the first dispensing unit at desired locations on thefirst electronic substrate pattern, wherein dispensing material from thefirst dispensing unit comprises lowering the first dispensing unittoward the first electronic substrate pattern; and dispensing materialfrom the second dispensing unit at desired locations on the secondelectronic substrate pattern, wherein dispensing material from thesecond dispensing unit comprises, lowering the second dispensing unittoward the second electronic substrate pattern. In certain embodiments,the predetermined distance is determined by identifying a first point ofreference associated with the first electronic substrate pattern and asecond point of reference associated with the second electronicsubstrate pattern.

Yet another exemplary dispense operation for two substrates may consistof the following steps: (1) calibrating the actual distance between eachof the dispensing units and the camera; (2) identifying the actualpositions of the fiducial locations on a substrate or on multiplesubstrates; (3) moving the first dispensing unit to a first dispenselocation on a first substrate; (4) dispensing at the first dispenselocation on the first substrate; (5) moving the second dispensing unitto the first dispense location on the second substrate, which is a smalland therefore rapidly performed movement; (6) dispensing at the firstdispense location on the second substrate; and (7) repeating steps (3)through (6) for each of the remaining dispense locations on thesubstrates. The foregoing operation may be performed when dispensing ona single substrate having multiple patterns on the substrate.

In other embodiments of the disclosure, a dual-lane conveyor isincorporated into the system to handle work pieces. In such systems, thedispense units continue to dispense on parts fixed on one conveyor lanewhile parts are loaded off of and onto another conveyor lane.

In still other embodiments of the disclosure, aspects of the dual-laneconveyor are incorporated into multiple pallet loading fixtures. In suchsystems, the dispense units continue to dispense on parts fixed on onepallet while parts are loaded off of and then onto another pallet.

In another example, reference may be made to FIG. 5. Specifically, whenthe substrates 12A, 12B are aligned, or in the form of multiple,identical patterns that are aligned with one another on the substrate,such with cell phone patterns, rather than engaging the first dispensingunit to dispense on the first substrate 12A and then the seconddispensing unit 16 to dispense on the second substrate 12B, the firstand second dispensing units 14, 16 may be operated simultaneously. Thus,with respect to the two substrates 12A, 12B shown in FIG. 5, the firstand second dispensing units 14, 16 may be moved by the beam 30 and thecarriage device 32 over locations A₁ and A₂, respectively, to dispenseon these locations of respective substrates 12A and 12B. After materialis dispensed, the beam 30 and the carriage device 32 may operated tomove the first and second dispensing units 14, 16 over locations B₂ andB₂, respectively, for performing dispense simultaneous operations onthese locations. This process may be repeated for each location untilall of the locations on the substrates 12A and 12B requiring materialare dispensed upon.

As mentioned above, the bracket 52 is coupled to the second dispensingunit 16 a predetermined distance D_(X), which may be extended andretracted so that it achieves a length that is equivalent to thedistance L_(X) between the first and second substrates. In a certainembodiment, the second dispensing unit 16 may be manually preset to adesired position. In other embodiments, the second dispensing unit 16may be automatically adjusted by a suitable mechanism provided on thebracket 52. As with the prior example, in this particular example, sincethe patterns on the first and second substrates 12A, 12B are identical,the locations A₂, B₂ and C₂ on the second substrate 12B correspond tothe locations A₁, B₁ and C₁ on the first substrate 12A so that themovement of the dispensing units 14, 16 places the dispensing unitsabove corresponding locations on the substrates. Z axis movement may beachieved by the independent Z drive mechanisms 34, 36 associated withthe first and second dispensing units 14, 16, respectively.

In one embodiment, the camera 38 is configured to capture an image of afirst pattern (e.g., a fiducial or a pattern landmark on substrate 12A)and to capture an image of a second pattern (e.g., a fiducial or apattern landmark on substrate 12B). The camera 38 may take one or moreimages of the substrate in order to obtain sufficient information as towhether the first and second patterns are aligned with one another.After taking the image or images, the controller 18 is configured toverify whether the first pattern and the second pattern are properlypositioned on the support with respect to one another based on theimage. If properly positioned, the dispensing units 14, 16 may becontrolled by the controller 18 to perform simultaneous dispenseoperations of the first dispensing unit on the first pattern and thesecond dispensing unit on the second pattern. As mentioned above, thedispensing units may be non-contact-type dispensing units that arecapable of streaming or launching material onto the substrate.

In the situation where the two patterns are not properly positioned, thedispenser may operate in the manner described above. For example, thefirst dispensing unit 14 may perform all of the dispense operations onthe first pattern. After completing the first pattern, the firstdispensing unit 14 or the second dispensing unit 16 may perform all ofthe dispense operations on the second pattern. In another example, thefirst dispensing unit 14 may perform some of the dispense operations ona first area of the first pattern. Next, the second dispensing unit 16may perform some of the dispense operations on a first area of thesecond pattern. After completing the first areas of the first and secondpatterns, the first and second dispensing units may sequentiallydispense material on subsequent areas of the first and second patternsin the manner described above.

In further examples, the substrate may include three or more patternsmay be provided, or three or more separate substrates may be provided.With either example, the camera 38 may be configured to capture imagesof each pattern as described above. After taking the images, thecontroller 18 may be configured to determine whether the patterns aresufficiently aligned for simultaneous dispensing. In one embodiment, thedispenser may be configured with any number of dispensing units todispense on the patterns. In other embodiments, the dispenser may beconfigured with two dispensing units as disclosed above, with onedispensing unit (e.g., dispensing unit 14) dispensing on the firstpattern and the other dispensing unit (e.g., dispensing unit 16)simultaneously dispensing on the third pattern. This approach may beparticularly desirable when adjacent patterns are positioned too closeto one another, thereby prohibiting the dispensing units from being ableto operate over adjacent patterns due to the relatively large sizes ofthe dispensing units. Once dispensing on the first and third patterns iscompleted, the dispenser may be configured to move the dispensing unitssuch that the first dispensing unit 14 is positioned over the secondpattern and the second dispensing unit 16 is positioned over the fourthpattern, if provided. This sequence of operation may continue untildispensing operations are performed on all of the patterns. For an oddnumber of patterns, the first dispensing unit 14 may be configured todispense material on the last pattern, while the second dispensing unit16 remains stationary.

It is further contemplated that when using more than two dispensingunits, that this approach of simultaneous dispensing on every otherpattern may be employed. For example, when using three dispensing units,the first, third and fifth patterns may be dispensed upon simultaneouslyby the first, second and third dispensing units, respectively. Afterdispensing on these patterns, the dispensing units may be moved so thatdispensing occurs on the second, fourth and sixth patterns with thefirst, second and third dispensing units, respectively.

In an exemplary embodiment, a method of dispensing material may includedelivering an electronic substrate to a dispense position, theelectronic substrate having at least two identical patterns, capturingat least one image of the at least two patterns, determining whether theat least two patterns are properly positioned to perform simultaneousdispense operations on the at least two patterns based on the capturedimage, and performing simultaneous dispense operations on the at leasttwo patterns if the two patterns are properly positioned.

Dispensing material may include positioning a first dispensing unit overa first location of a first pattern and positioning a second dispensingunit over a first location of a second pattern. As discussed above, thesecond dispensing unit may be spaced from the first dispensing unit apredetermined distance. Specifically, material may be dispensed from thefirst and second dispensing units on respective first locations of thefirst and second patterns. Once dispensing takes place, the firstdispensing unit is moved over a second location of the first pattern andthe second dispensing unit is simultaneously moved over a secondlocation of the second pattern of the electronic substrate. Once moved,material may be dispensed from the first and second dispensing units onrespective second locations of the first and second patterns.

In another exemplary embodiment, a method of dispensing material mayinclude (1) identifying positions of more than one location on anelectronic substrate, (2) determining whether a dispense location of afirst pattern and a dispense location of a second pattern are properlypositioned to perform simultaneous dispense operations on the first andsecond patterns based on the identified positions, (3) moving a firstdispensing unit to a dispense location on the first pattern and a seconddispensing unit to a dispense location on the second pattern, thedispense location of the first pattern corresponding with the dispenselocation on the second pattern, (4) dispensing at the first dispenselocation on the first pattern with the first dispensing unit and at thefirst dispense location on the second pattern with the second dispensingunit, and (5) repeating steps (3) and (4) for each remaining dispenselocation on the first and second patterns of the electronic substrate.As discussed above, prior to performing the method, a distance betweenthe first dispensing unit 14 and the camera 38 and the distance betweenthe second dispensing unit 16 and the camera 38 may be calibrated.

Having thus described several aspects of at least one embodiment of thisdisclosure, it is to be appreciated various alterations, modifications,and improvements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis disclosure, and are intended to be within the spirit and scope ofthe disclosure. Accordingly, the foregoing description and drawings areby way of example only.

1. A dispensing apparatus comprising: a frame; a support coupled to theframe, the support being configured to support at least one electronicsubstrate; a gantry coupled to the frame; a first dispensing unitcoupled to the gantry, the first dispensing unit being configured todispense material; a second dispensing unit coupled to the gantry, thesecond dispensing unit being configured to dispense material; an imagingsystem coupled to one of the frame and the gantry, the imaging systembeing configured to capture at least one image of a first pattern and asecond pattern, the second pattern being identical to the first pattern;and a controller configured to verify whether the first pattern and thesecond pattern are properly positioned on the support with respect toone another based on the at least one captured image and configured toenable the dispensing apparatus to perform simultaneous dispenseoperations of the first dispensing unit on the first pattern and thesecond dispensing unit on the second pattern.
 2. The dispensingapparatus of claim 1, wherein the gantry comprises at least one Z drivemechanism configured to support and lower the first dispensing unit andthe second dispensing unit when performing a dispense operation with atleast one of the first dispensing unit and the second dispensing unit.3. The dispensing apparatus of claim 2, wherein the at least one Z drivemechanism comprises a first Z drive mechanism configured to support thefirst dispensing unit, the first Z drive mechanism being configured tolower the first dispensing unit toward the first pattern when performinga dispense operation, and a second Z drive mechanism configured tosupport the second dispensing unit, the second Z drive mechanism beingconfigured to lower the second dispensing unit toward the second patternwhen performing a dispense operation.
 4. The dispensing apparatus ofclaim 1, wherein the second dispensing unit is capable of being adjusteda predetermined distance from the first dispensing unit based on the atleast one captured image.
 5. The dispensing apparatus of claim 1,wherein the first and second dispensing units each comprise anon-contact-type dispensing unit.
 6. The dispensing apparatus of claim5, wherein the non-contact-type dispensing unit is configured to streammaterial onto the electronic substrate.
 7. The dispensing apparatus ofclaim 5, wherein the non-contact-type dispensing unit is configured tolaunch material at a location on the electronic substrate.
 8. Adispensing apparatus comprising: a gantry; at least two dispensing unitscoupled to the gantry, each of the at least two dispensing unitsincluding a non-contact-type dispensing unit configured to dispensematerial; an imaging system coupled to the gantry, the imaging systembeing configured to capture at least one image of a first pattern and asecond pattern, the second pattern being identical to the first pattern;and a controller configured to verify whether the first pattern and thesecond pattern are properly positioned on a support with respect to oneanother based on the at least one captured image and configured toenable the dispensing apparatus to perform simultaneous dispenseoperations of the first dispensing unit on the first pattern and thesecond dispensing unit on the second pattern.
 9. The dispensingapparatus of claim 8, wherein the non-contact-type dispensing unit isconfigured to stream material onto an electronic substrate.
 10. Thedispensing apparatus of claim 8, wherein the non-contact-type dispensingunit is configured to launch material at a location on an electronicsubstrate.